Utils.js

import { readFileSync } from 'fs';
function bitmapDiff(imagePath, expectedImagePath) {
  const PNG = require('pngjs').PNG;
  const pixelmatch = require('pixelmatch');
  const img1 = PNG.sync.read(readFileSync(imagePath));
  const img2 = PNG.sync.read(readFileSync(expectedImagePath));
  const { width, height } = img1;
  const diff = new PNG({ width, height });

  return pixelmatch(img1.data, img2.data, diff.data, width, height, { threshold: 0.0 });
}
const utils = {
  elementByLabel: (label) => {
    // uncomment for running tests with rn's new arch
    // return element(by.label(label)).atIndex(0);
    return element(by.text(label));
  },
  elementById: (id) => element(by.id(id)),
  elementByTraits: (traits) => element(by.traits(traits)),
  elementByType: (type) => element(by.type(type)),
  elementTopBar: () => {
    const elementType = (device.getPlatform() === 'ios') ?
      'UINavigationBar' :
      'com.reactnativenavigation.views.stack.topbar.TopBar';
    return utils.elementByType(elementType);
  },
  tapBackIos: () => {
    try {
      return element(by.traits(['button']).and(by.label('Back')))
        .atIndex(0)
        .tap();
    } catch (err) {
      return element(by.type('_UIModernBarButton').and(by.label('Back'))).tap();
    }
  },
  sleep: (ms) => new Promise((res) => setTimeout(res, ms)),
  expectImagesToBeEqual: (imagePath, expectedImagePath) => {
    let diff = bitmapDiff(imagePath, expectedImagePath);
    if (diff !== 0) {
      throw Error(`${imagePath} should be the same as ${expectedImagePath}, with diff: ${diff}`);
    }
  },
  expectImagesToBeNotEqual: (imagePath, expectedImagePath) => {
    let diff = bitmapDiff(imagePath, expectedImagePath);
    if (diff === 0) {
      throw Error(`${imagePath} should be the same as ${expectedImagePath}, with diff: ${diff}`);
    }
  },
};

export default utils;